According to the Endocrine Society, BSSM, European Male Ageing Study, and International Society of Urology, TRT is also not recommended in men with a palpable prostate nodule or induration, as well as in men with a PSA level > 4 ng/mL or a PSA > 3 ng/mL combined with a high risk of prostate cancer. Here, KLK3 is linked to Familial prostate cancer.